1. Field of the Invention
In the specification, drawings, and claims of this application (hereinafter referred to as “this specification and the like”), a semiconductor device, an electronic component, an electronic device, operating methods thereof, and manufacturing methods thereof are described, for example.
In this specification and the like, a semiconductor device means a device that utilizes semiconductor characteristics and refers to a circuit including a semiconductor element (e.g., a transistor, a diode, or a photodiode), a device including the circuit, and the like. The semiconductor device also means any device that can function by utilizing semiconductor characteristics. For example, an integrated circuit, a chip including an integrated circuit, and an electronic component including a chip in a package are examples of semiconductor devices. Moreover, a memory device, a display device, a light-emitting device, a lighting device, an electronic device, and the like themselves might be semiconductor devices, or might each include a semiconductor device.
2. Description of the Related Art
For pixels of an active matrix display device using light-emitting elements, a variety of circuit configurations have been proposed. In general, a pixel is provided with at least a light-emitting element, a selection transistor that controls input of a grayscale signal to the pixel, and a driving transistor that drives the light-emitting element. Supplying a drain current flowing through the driving transistor to the light-emitting element enables the light-emitting element to emit light with a luminance corresponding to the value of the drain current.
Therefore, in the case where electrical characteristics (e.g., threshold voltage, field-effect mobility) of the driving transistor vary among a plurality of pixels that constitute a screen of a display device, variations in luminance of the light-emitting element are generated even when grayscale signals with the same voltage are supplied. Variations in electrical characteristics of the driving transistor among a plurality of pixels are one of the causes of reduction in display quality of a display device.
For active matrix display devices, the number of pixels provided has been increased to achieve higher resolution, and hundreds of thousands to tens of millions of pixels are provided in one display device. In a general color display device, a pixel is composed of three subpixels corresponding to display colors of red, green, and blue (RGB). For example, in the case where the resolution of a display device is full-HD, the number of subpixels is 1366×768×3 (RGB)=1,049,088; and in the case where the resolution is 8K4K (Super Hi-Vision), the number of subpixels is 7,680×4,320×3 (RGB)=33,177,600. It is very difficult for driving transistors of a large number of different subpixels to have perfectly the same electrical characteristics. Thus, measuring the electrical characteristics of a driving transistor and correcting the luminance of a light-emitting element is proposed (e.g., Non-Patent Document 1).
In order to meet demands for a larger number of gray levels and higher resolution of a display portion or the like, a dedicated IC (driver IC) is used in a driver circuit of a display device, particularly in a source driver circuit where a data signal is generated from a video signal (see Patent Document 1, for example).